Flood Management: The Soft Path

New Orleans under water, 2005. Photo: FEMA

Floods are the most destructive, most frequent and most costly natural disasters on earth. Flood damages have soared in recent decades, despite the expenditure of hundreds of billions of dollars on flood control structures. Dams and levees can never be fail-proof, and when they fail, they do so spectacularly and sometimes catastrophically. They also provide a false sense of security that encourages risky development on vulnerable floodplains. Improving our ability to cope with floods requires adopting a more sophisticated set of techniques than dams and levees – the “soft path” of flood risk management, which aims to understand, adapt to and work with the forces of nature.

Climate change is expected to dramatically increase flood risk. Structural flood control is based on the assumption of a fictional static climate. The inflexibility of hard flood control is a major weakness.

"Soft-path" flood risk management is flexible, in that it seeks to reduce damage to any size of flood, and adaptive in that it seeks to respond to the hydrological changes caused by changing land use and river morphology. Flood risk management assumes that floods will happen and that we need to learn to live with them as best we can, reducing their speed, size and duration where possible, doing our best to protect our most valuable assets, and get out of their destructive path. It assumes that all flood protection infrastructure can fail and that this failure must be planned for. It is also based on an understanding that all floods are not inherently bad – and indeed that floods are essential for the health of riverine ecosystems.